Gas-fired dishwasher



Nov. 26, 1963 J. w. CLAYWELL GAS-FIRED DISHWASHER 2 Sheets-Sheet 1 FiledMarch 5, 1961 v m w m Nov. 26, 1963 J.'W. CLAYWELL GAS-FIRED DISHWASHER2 Sheets-Sheet 2 Filed March 3, 1961 United States Patent 3,111,953GAS-FIRED DISHWASHER Jack W. Claywell, Wisconsin Rapids, Wis., assignorto Preway Inc., a corporation of Wisconsin Filed Mar. 3, 1961, Ser. No.93,120 Claims. (Cl. 134107) This invention relates to a dishwasher nadmore particularly to a dishwasher utilizing gas for heating of waterused therewith.

An object of this invention is to provide a new and improved gasdishwasher.

Another object of this invention is to provide a dishwasher having a tubwith a bottom, water circulating means in the form of an impeller andalso a drain located centrally of the tub bottom, and means disposedbeneath the tub bottom and spanning a substantial part of the tub bottomproviding a chamber into which flame from a gas burner is directedwhereby the hot gases pass along a substantial part of the tub bottomunderside and are then exhausted from the chamber to obtain heating ofthe water within the tub quickly and economically.

A further object of the invention is to provide a dishwasher as definedin the preceding paragraph in which the chamber beneath the tub bottomis defined by a generally U-shaped frame secured to the tub bottom, saidframe being generally trough-like, whereby the chamber permits thepassage of gases therethrough, and the frame having a pair of openingswith the burner associated with one opening and an air blower associatedwith the other open ing for drawing gases from the chamber and mixingthe gases with air for exhaust from the dishwasher, and a plurality offins within the chamber to increase the heat exchange.

Further objects and advantages will become apparent from the followingdetailed description taken in connection with the accompanying drawingsin which:

FIG. 1 is a perspective elevational view of a gas dishwasher with thefront loading door open;

FIG. 2 is a horizontal section on an enlarged scale taken generallyalong the line 2--2 in FIG. 1;

FIG. 3 is a perspective detail view of the water heating componentsassociated with the dishwasher;

FIG. 4 is a fragmentary front elevational view of the lower part of thedishwasher;

FIG. 5 is a fragmentary side elevational view of the lower part of thedishwasher taken of the side opposite from that shown in FIG. 4;

FIG. 6 is a schematic view of the gas system associated with thedishwasher; and

FIG. 7 is a sectional view taken generally along the line 77 in FIG. 2.

While this invention is susceptible of embodiment in many diiferentforms, there is shown in the drawings and will herein be described indetail an embodiment of the invention with the understanding that thepresent disclosure is to be considered as an exemplification of theprinciples of the invention and is not intended to limit the inventionto the embodiment illustrated. The scope of the invention will bepointed out in the appended claims.

The dishwasher embodies a cabinet 10 in which a tub is positioned havinga bottom plate 11 and the cabinet has a front loading door 12 all as isconventionally known in the art. The tub bottom plate 11 has a centralfiat section 15 and upwardly sloped surrounding sections 16, 17, 18 and19 on the four sides of the central section. The central section '15 haswater circulating means for the tub in the form of a conventionalimpeller 20 which is positioned above the tub bottom plate and which isdriven from a motor 21 positioned beneath the tub bottom plate 11. Thecentral section also has a drain 22 which communicates with a boot 23beneath the tub bot tom plate and which has a drain pump 24 associatedtherewith for draining water from the tub. The boot 23 also has a line25 extending there-from to a water fill detection switch 26.

In order to heat water within the tub quickly and economically, a gassystem is associated therewith and embodies a trough-like frameindicated generally at 30 having a generally U-shaped configuration withan inner side wall 31 and an outer side wall 32. As is evident fromFIGS. 3 and 7, the side walls 31 and 32 are of different height tocompensate for the slope of the tub bottom plate 11. A frame bottom 33spans the side walls and the ends of the frame are enclosed by end walls34 and 35. The side Walls 31 and 32 have turned-out flanges 36 and 37,respectively, whereby the frame is secured to the underside of the tubbottom plate 11 by suitable means such as welding. It will be seen thatthe frame 30 in association with the bottom plate defines a heatexchange chamber of a U-shape which partially surrounds the conventionalwasher components located beneath the tub bottom plate 11. The frame 30has a pair of openings 40 and 41 at the opposite ends thereof in theframe bottom 33 with the opening 40 having a gas burner 42 disposedthere beneath. The gas burner 42 is suspended from the frame 30 by abracket 43 which holds the outlet end of the burner in position beneaththe frame opening 40.

The opening 41 in the frame 30 overlies a blower 44 driven by a motor 45and the blower scroll 46 has its inlet supported in spaced relation withthe opening 41 by a bracket 47. The bracket 47 has openings 48 thereinwhereby external air may enter the blower inlet as well as gases comingfrom the heat exchange chamber. An outlet 49 for the blower liesdirectly behind a screen 50 at the front of the dishwasher cabinet,whereby the gases exhausted from the heat exchange chamber and whichhave been cooled and diluted by air coming in through the openings 48are exhausted from the dishwasher.

The heat exchange rate is increased by having a pair of upstanding fins51 and 52 disposed within the heat exchange chamber and having flangesfor suitable attachment to the underside of the tub bottom plate 11. Asshown in FIG. 7, suitable heat insulation 53 encloses the frame walls31, 32 and 33. This element has been omitted from the other views forclarity.

The gas system is shown particularly in FIGS. 3, 5 and 6 in which theburner 42 receives gas from a supply line which connects to a maincontrol valve 61 with an outlet line 62 therefrom leading to a solenoidvalve 63 which controls the supply of gas through a line 64 to theburner. A branch line 65 supplies gas to a burner pilot 66 which isdisposed adjacent the burner 42 with a thermocouple line 67 connectingthe pilot to the main valve 61 to control supply of gas to the burnerdependent upon operation of the pilot.

Water for the dishwasher is supplied through a valve 70 connectable to awater line, not shown, with water passing to the tub through a fill line71.

It will be seen from the foregoing that a heat exchange chamber has beenassociated with the dishwasher to cover a substantial area of the tubbottom plate underside, to obtain as much heat transfer as possible,while still allowing the placement of the conventional dishwashercomponents in their generally conventional locations.

I claim:

1. In a dishwasher, in combination, a tub having a bottom, an impellerpositioned centrally within the tub above the bottom [for circulatingwater in the tub, a motor for the impeller beneath said tub bottom, awater drain system for the tub including a central drain in the tubbottom and a drain pump beneath the bottom and means for heating waterin the tub including a generally U-shaped 3 frame beneath and secured tothe tub bottom disposed about the central area having the drain andimpeller to define a U-shaped chamber, a gas burner operativelyassociated with one end of the chamber for passing hot gases thereto,and an air blower operatively connected with the other end for drawingthe gases through the chamber and having external air inlets whereby thegases and air mix prior to room discharge.

2. A dishwasher as defined in claim 1 in which fin means are disposed insaid chamber and touching said bottom to facilitate heat transfer.

3. In a dishwasher, in combination, a tub having a bottom, an impellerpositioned centrally within the tub above the bottom for circulatingwater in the tub, a motor for the impeller beneath said tub bottom, awater drain system for the tub including a central drain in the tubbottom, and means for heating water in the tube including an elongateframe spaced from and secured to the tub bottom and having an opening ateach end, a gas burner positioned adjacent one opening for directing aflame and heated gases into said chamber, and a blower having an inletadjacent to the other frame opening for exhausting gases from thechamber.

4. In a dishwasher, a tub having a bottom plate with a central flat areaand upwardly sloped surrounding sections, means Within the tub forcirculating water, and

water heating means beneath the bottom plate including an elongatetrough-like frame secured to said tub bottom plate and spanning asubstantial part of said bottom plate to define a closed heat exchangechamber except for an opening at each end of said frame, a burneroperatively associated with one frame opening, and a blower operativelyconnected with the other frame opening and additionally having externalair inlets for mixing external air with the exhaust from said chamber.

5. A dishwasher as defined in claim 4 in which said trough-like framehas opposite side walls of different heights to compensate for the slopeof the bottom plate surrounding sections and a plurality of heatexchanger fins are positioned in said chamber.

References Cited in the file of this patent UNITED STATES PATENTS1,559,727 Merseles et a1. Nov. 3, 1925 2,170,730 Rodieck Aug. 22, 19392,226,816 Hepburn Dec. 31, 1940 2,385,854 Wolfersperger Oct. 2, 19452,825,349 Keliher et al Mar. 4, 1958 FOREIGN PATENTS 621,168 France Jan.31, 1927 1,171,345 France Jan. 23, 1959

3. IN A DISHWASHER, IN COMBINATION, A TUB HAVING A BOTTOM, AN IMPELLERPOSITIONED CENTRALLY WITHIN THE TUB ABOVE THE BOTTOM FOR CIRCULATINGWATER IN THE TUB, A MOTOR FOR THE IMPELLER BENEATH SAID TUB BOTTOM, AWATER DRAIN SYSTEM FOR THE TUB INCLUDING A CENTRAL DRAIN IN THE TUBBOTTOM, AND MEANS FOR HEATING WATER IN THE TUBE INCLUDING AN ELONGATEFRAME SPACED FROM AND SECURED TO THE TUB BOTTOM AND HAVING AN OPENING ATEACH END, A GAS BURNER POSITIONED ADJACENT ONE OPENING FOR DIRECTING AFLAME AND HEATED GASES INTO SAID CHAMBER, AND A BLOWER HAVING AN